The present invention relates generally to a method of treating ligno-cellulosic materials such as ligneous vegetable matter for the removal of lignin and other non-carbohydrates as well as non-cellulosic carbohydrates from cellulosic matter. More specifically the invention relates to the impregnation of such ligno-cellulosic materials with a liquor and the rapid heating of same for the removal of lignin and other non-carbohydrates as well as non-cellulosic carbohydrates from cellulosic matter. The present invention provides for the rapid disolution of lignin and other non-carbohydrates from ligno-cellulosic materials using triethyleneglycol and catalytic amounts of an organic acid for the purpose of producing pulp or as a pre-hydrolysis step for the production of alcohols and other organic chemicals.
It is known that it is highly advantageous to derive useful products such as furfural compounds from ligneous carbohydrate materials occuring naturally in abundance. It is also highly advanteous to economically and expediently derive lignin from the same material for converting cellulosic materials of such matter, when desired, into pulp useful in the paper-making industry and for converting residual carbohydrate fractions into other commercially useful products. A liquor and a method for doing the above is disclosed in U.S. Pat. No. 3,442,753 issued May 6, 1969 to the present inventor. U.S. Pat. No. 3,442,753 and its continuation-in-part, U.S. Pat. No. 3,522,230 issued July 28, 1970 are both herewith incorporated by reference.
The processing costs of the method taught in U.S. Pat. No. 3,442,753 are highly dependent on the amount of liquor used, and the amount of time and energy needed in heating of ligneous vegetable matter.
Therefore it is an object of the present invention to provide a liquor efficient method of treating ligno-cellulosic matterials.
It is another object of the present invention to provide a method of ligno-cellulosic material treatment that requires only 1/3 to 1/2 the liquor required in known prior art methods.
Still another object of the present invention is to provide a method of lignin removal that requires much shorter heating times than that taught in the known prior art.